Flaky test: TestNetworkDBCRUDMediumCluster (libnetwork)

[thaJeztah]

Seen failing on Windows RS5 #42005 https://ci-next.docker.com/public/job/moby/job/PR-42005/6/execution/node/270/log/?consoleFull

=== RUN   TestNetworkDBCRUDMediumCluster
2021/06/07 07:36:57 Closing DB instances...
time="2021-06-07T07:36:57Z" level=error msg="node: c784143724ad is unknown to memberlist"
time="2021-06-07T07:36:58Z" level=error msg="node: c0a70b8886f7 is unknown to memberlist"
--- FAIL: TestNetworkDBCRUDMediumCluster (9.68s)
    networkdb_test.go:117: Network existence verification failed

windowsRS5-integration-bundles.zip

[thaJeztah]

Seen failing again, now on #42559, Windows 2022, but this time due to a timeout; https://ci-next.docker.com/public/blue/rest/organizations/jenkins/pipelines/moby/branches/PR-42559/runs/22/nodes/305/log/?start=0

=== RUN   TestNetworkDBCRUDMediumCluster
    networkdb_test.go:420: timeout hit after 20s: node2:Waiting for cluser peers to be established
--- FAIL: TestNetworkDBCRUDMediumCluster (22.34s)

win-2022-integration-bundles-3.zip